Bolus delivery device

ABSTRACT

A bolus delivery device is provided that comprises a housing and a reservoir defined by an activation dome and a reservoir seat and disposed within the housing for receipt of a volume of a fluid. The bolus delivery device further comprises a bladder disposed in the housing that is in fluid communication with the reservoir for receipt of the fluid from the reservoir; an actuator; an inlet conduit in fluid communication with the reservoir for providing the fluid to the reservoir; and an outlet conduit in fluid communication with the bladder for providing the fluid to a patient. The actuator is in operative communication with the reservoir to initiate a flow of the fluid from the reservoir to the bladder. The bladder expands as the bladder receives the fluid and contracts as the bladder dispenses the fluid. An infusion assembly including a bolus delivery device also is provided.

RELATED APPLICATION

The present application is the national stage entry of InternationalPatent Application No. PCT/US2018/028112 having a filing date of Apr.18, 2018, which claims priority to U.S. Provisional Application Ser. No.62/516,165, filed on Jun. 7, 2017, both of which are incorporated hereinin their entirety by reference thereto.

FIELD

The present invention relates to fluid dispensing apparatus and pertainsparticularly to infusion assemblies having features for administering abolus dose of fluid.

BACKGROUND

In instances of severe pain, infection, and other medical ailments, ithas been proven beneficial to administer a continuous flow of medicinalfluid to a patient through a catheter-based system. There are many typesof medicinal fluids that can be administered in this manner including,but not limited to, insulin, analgesics, and antibiotics. Often,patients are intravenously supplied with the medicinal fluid, e.g., apharmaceutically active liquid, at a controlled rate over a long periodof time. The medicinal fluid also may be delivered to a patient'sintramuscular space. Preferably, such infusion is accomplished while thepatient is in an ambulatory state. Typically, an infusion assemblyincludes an inflatable elastomeric pump forming a liquid container thatis supported by a mandrel, as well as a flow control valve or device andtubing for supply of the liquid to the patient. The walls of the pumpare forced to expand when filled with the liquid and provide pressurefor expelling the liquid.

Some infusion assemblies include a device for providing a bolus of themedicinal fluid, often with patient or user operable actuators such thatthe patient or another user can initiate the administration of bolusdoses. However, typical bolus delivery devices may not preventover-filling of the bolus reservoir, which could lead toover-administration of the medication. Further, the bolus reservoir mayleak fluid, which can affect the volume of the bolus dose, as well ascan be messy and inconvenient for the user.

Accordingly, bolus delivery devices that include one or more safetymechanisms for preventing over-administration of medication, as well asone or more features for preventing leaks from the bolus reservoir,would be desirable. Infusion assemblies incorporating such improve bolusdelivery devices also would be advantageous.

SUMMARY

Aspects and advantages of the invention will be set forth in part in thefollowing description, or may be obvious from the description, or may belearned through practice of the invention.

In one aspect, the present subject matter is directed to a bolusdelivery device. The bolus delivery device comprises a housing and areservoir disposed within the housing for receipt of a volume of afluid. The reservoir is defined by an activation dome and a reservoirseat. The bolus delivery device further comprises a bladder disposed inthe housing. The bladder is in fluid communication with the reservoirfor receipt of the fluid from the reservoir. The bolus delivery devicealso comprises an actuator; an inlet conduit in fluid communication withthe reservoir for providing the fluid to the reservoir; and an outletconduit in fluid communication with the bladder for providing the fluidto a patient. The actuator is in operative communication with thereservoir to initiate a flow of the fluid from the reservoir to thebladder. The bladder expands as the bladder receives the fluid andcontracts as the bladder dispenses the fluid. It should be understoodthat the bolus delivery device may be further configured with any of theadditional features as described herein.

In some embodiments, the reservoir seat is located between theactivation dome and the bladder such that the reservoir seat is distalto the activation dome and proximal to the bladder. Also, the bolusdelivery device may comprise a piston axially disposed within thereservoir and extending through an orifice in the reservoir seat, thepiston having a proximal end and a distal end; a seal member disposedaround the distal end of the piston and against a distal side of theorifice in the reservoir seat; and a biasing member disposed around thedistal end of the piston. In such embodiments, the activation dome isconnected to the actuator and the proximal end of the piston such thatoperating the actuator displaces the piston to displace the seal memberand initiate the flow of fluid from the reservoir to the bladder. Insome embodiments, the seal member is free to slide along the piston.Further, the reservoir has a fluid pressure that varies as the volume ofthe fluid varies within the reservoir, and the biasing member has abiasing force that overcomes the fluid pressure of the reservoir whenthe reservoir is substantially empty. Additionally, a collar may bedisposed between the seal member and the biasing member, e.g., to moreevenly distribute the pressure of the biasing member about the sealmember to aid in the sealing force of the biasing member.

In some embodiments, the housing defines ribs that limit the expansionof the bladder. In still other embodiments, the inlet conduit is influid communication with an elastomeric pump. Moreover, the bladder mayextend between a proximal connector and a distal connector, and in suchembodiments, the inlet conduit is in fluid communication with the distalconnector and the outlet conduit is in fluid communication with thedistal connector. An O-ring may secure a proximal end of the bladder tothe proximal connector and another O-ring may secure a distal end of thebladder to the distal connector. Further, the bolus delivery device mayinclude an internal conduit extending from the distal connector to thereservoir. The internal conduit provides fluid communication between theinlet conduit and the reservoir.

In yet other embodiments, the bolus delivery device comprises a stopthat catches in a groove defined in the actuator to limit the distalmovement of the actuator. Additionally or alternatively, the actuatormay be operable by the patient to initiate a release of fluid from thebolus delivery device to the patient. In such embodiments, the actuatoris configured such that it requires minimal effort to force the fluidout of the bolus delivery device and that, when actuated by the patient,fluid is permitted to flow out of the bolus delivery device to thepatient without further action by the patient. Further, the bolusdelivery device also may comprise a removable tab that holds theactuator in a depressed position to self-prime the bolus deliverydevice.

In another aspect, the present subject matter is directed to an infusionassembly. The infusion assembly comprises an elastomeric pump configuredto provide a fluid under pressure; a continuous flow path in fluidcommunication with the pump for providing a continuous and substantiallyconstant flow rate of fluid from the pump; a bolus flow path for thedelivery of a bolus dose of the fluid; and a bolus delivery device influid communication with the bolus flow path and configured to receivefluid from the pump. The bolus delivery device includes a housing and areservoir disposed within the housing for receipt of a volume of afluid. The reservoir is defined by an activation dome and a reservoirseat. The bolus delivery device further comprises a bladder disposed inthe housing. The bladder is in fluid communication with the reservoirfor receipt of the fluid from the reservoir. The bolus delivery devicealso comprises an actuator; an inlet conduit in fluid communication withthe reservoir for providing the fluid to the reservoir; and an outletconduit in fluid communication with the bladder for providing the fluidto a patient. The actuator is in operative communication with thereservoir to initiate a flow of the fluid from the reservoir to thebladder. The bladder expands as the bladder receives the fluid andcontracts as the bladder dispenses the fluid. It should be understoodthat the infusion assembly may be further configured with any of theadditional features as described herein.

In some embodiments, the pump provides the fluid under a pressure of upto about 30 psi. In other embodiments, the pump provides the fluid undera pressure within a range of about 10 psi to about 30 psi. In stillother embodiments, the pump provides the fluid under a pressure within arange of about 15 psi to about 25 psi.

Moreover, in some embodiments, the reservoir seat is located between theactivation dome and the bladder such that the reservoir seat is distalto the activation dome and proximal to the bladder. Also, the bolusdelivery device of the infusion assembly may comprise a piston axiallydisposed within the reservoir and extending through an orifice in thereservoir seat, the piston having a proximal end and a distal end; aseal member disposed around the distal end of the piston and against adistal side of the orifice in the reservoir seat; and a biasing memberdisposed around the distal end of the piston. In such embodiments, theactivation dome is connected to the actuator and the proximal end of thepiston such that operating the actuator displaces the piston to displacethe seal member and initiate the flow of fluid from the reservoir to thebladder. In some embodiments, the seal member is free to slide along thepiston. Further, the reservoir has a fluid pressure that varies as thevolume of the fluid varies within the reservoir, and the biasing memberhas a biasing force that overcomes the fluid pressure of the reservoirwhen the reservoir is substantially empty.

In some embodiments, the housing defines ribs that limit the expansionof the bladder. In still other embodiments, the inlet conduit is influid communication with an elastomeric pump. Moreover, the bladder mayextend between a proximal connector and a distal connector, and in suchembodiments, the inlet conduit is in fluid communication with the distalconnector and the outlet conduit is in fluid communication with thedistal connector. An O-ring may secure a proximal end of the bladder tothe proximal connector and another O-ring may secure a distal end of thebladder to the distal connector. Further, the bolus delivery device ofthe infusion assembly may include an internal conduit extending from thedistal connector to the reservoir. The internal conduit provides fluidcommunication between the inlet conduit and the reservoir.

In yet other embodiments, the bolus delivery device of the infusionassembly comprises a stop that catches in a groove defined in theactuator to limit the distal movement of the actuator. Additionally oralternatively, the actuator may be operable by the patient to initiate arelease of fluid from the bolus delivery device to the patient. In suchembodiments, the actuator is configured such that it requires minimaleffort to force the fluid out of the bolus delivery device and that,when actuated by the patient, fluid is permitted to flow out of thebolus delivery device to the patient without further action by thepatient. Further, the bolus delivery device of the infusion assemblyalso may comprise a removable tab that holds the actuator in a depressedposition to self-prime the bolus delivery device.

These and other features, aspects, and advantages of the presentinvention will become better understood with reference to the followingdescription and appended claims. The accompanying drawings, which areincorporated in and constitute a part of this specification, illustrateembodiments of the invention and, together with the description, serveto explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including thebest mode thereof, directed to one of ordinary skill in the art, is setforth in the specification, which makes reference to the appendedfigures, in which:

FIG. 1 is a schematic view of an infusion assembly having a bolusdelivery device according to an exemplary embodiment of the presentsubject matter.

FIG. 2 is a side perspective view of the bolus delivery device of FIG.1.

FIG. 3A is a side view of the bolus delivery device of FIG. 1 with aportion of a housing of the device removed and with a tab installed todepress an actuator of the device for self-priming the device.

FIG. 3B is the side view of FIG. 3A with the tab removed.

FIG. 3C is the side view of FIG. 3B with compression collar of thedevice shown as transparent, rather than as opaque as in FIG. 3B.

FIG. 4 is an axial cross-section view of the bolus delivery device ofFIG. 1, with a reservoir of the device at its maximum volume and abladder of the device in a fully relaxed state.

FIG. 5 is an axial cross-section view of the bolus delivery device ofFIG. 1, with a reservoir of the device at its minimum volume and abladder of the device in a fully expanded state.

FIG. 6 is a close-up view of a distal portion of the bolus deliverydevice of FIG. 4.

FIG. 7 is a close-up view of a distal portion of the bolus deliverydevice of FIG. 5.

DETAILED DESCRIPTION

Reference now will be made in detail to embodiments of the invention,one or more examples of which are illustrated in the drawings. Eachexample is provided by way of explanation of the invention, notlimitation of the invention. In fact, it will be apparent to thoseskilled in the art that various modifications and variations can be madein the present invention without departing from the scope or spirit ofthe invention. For instance, features illustrated or described as partof one embodiment can be used with another embodiment to yield a stillfurther embodiment. Thus, it is intended that the present inventioncovers such modifications and variations as come within the scope of theappended claims and their equivalents.

Moreover, the particular naming of the components, capitalization ofterms, the attributes, data structures, or any other programming orstructural aspect is not mandatory or significant, and the mechanismsthat implement the invention or its features may have different names,formats, or protocols. Also, the particular division of functionalitybetween the various components described herein is merely exemplary andnot mandatory; functions performed by a single component may instead beperformed by multiple components, and functions performed by multiplecomponents may instead performed by a single component.

Further, the detailed description uses numerical and letter designationsto refer to features in the drawings. Like or similar designations inthe drawings and description have been used to refer to like or similarparts of the invention. As used herein, the terms “first,” “second,” and“third” may be used interchangeably to distinguish one component fromanother and are not intended to signify location or importance of theindividual components.

Referring to the drawings, FIG. 1 provides a side view of an infusionassembly, e.g., for dispensing a fluid to a patient, according to anexemplary embodiment of the present subject matter. As shown, theexemplary infusion assembly 100 includes an elastomeric pump 102 havingan upper support member 104 and a lower support member 106. Infusionassembly 100 defines an axial direction A, and lower support member 106is spaced apart from upper support member 104 along the axial directionA.

More particularly, pump 102 defines a reservoir that serves as apressurized fluid source, holding medicinal fluid, such as localanesthetics, and providing a source of fluid under pressure. Pump 102forces the medicinal fluid through a tubing or conduit 108. Conduit 108forms a continuous flow path 110 for delivery of the medicinal fluidinto a wound site nerve bundle or the blood stream of a patient P. Inthe depicted exemplary embodiment, conduit or tubing 108 defines anoutlet 112 connecting the continuous flow path 110 to a catheter 114that delivers the medicinal fluid to patient P. In such embodiments,conduit 108 and catheter 114 may together define continuous flow path110 from pump 102 to patient P.

Further, in some embodiments, infusion assembly 100 may be configured toprovide for bolus delivery. In such configurations, conduit 108 maysplit into a continuous or primary flow path 110 and a controlled bolusflow path 140. Thus, medicinal fluid may be delivered into a wound sitenerve bundle or the blood stream of patient P from pump 102 via thecontinuous or primary flow path or from a bolus delivery device 200 viathe controlled bolus flow path. The bolus delivery device 200 isdescribed in greater detail below.

Pump 102 preferably accommodates a volume from about 100 to 500 ml offluid under a pressure of up to approximately 30 psi. In someembodiments, the pump may hold the fluid under a pressure of about 10psi to about 30 psi and, in other embodiments, under a pressure of about15 psi to about 25 psi. More particularly, pump 102 has an inner core116 extending between upper support member 104 and lower support member106 along axial direction A. Inner core 116 is surrounded by anelastomeric bladder 118 within a housing 120. Inner core 114 preferablyhas an inlet port 122, e.g., to fill bladder 118 with fluid, and anoutlet port 124 in fluid communication with conduit 108, e.g., todispense the fluid from bladder 118 to patient P through flow path 110.Fluid is held under pressure within elastomeric bladder 118 and flowsfrom elastomeric bladder 118 into conduit 108 through outlet port 124,preferably flowing at a controlled and predictable rate. Alternatively,conduit 108 may be sized to serve as a flow restrictor. Further,elastomeric bladder 118 preferably is constructed from a resilientmaterial that may comprise a variety of elastomeric compositions wellknown in the art, including vulcanized synthetic polyisoprenes, naturallatex, natural rubber, synthetic rubber, silicone rubber, or the like.

Exemplary pumps are described in U.S. Pat. Nos. 7,959,623 and 5,254,481,which are hereby incorporated by reference. A variety of otherconventional pumps also may be used. For example, the pumps described inU.S. Pat. Nos. 5,080,652 and 5,105,983, which are hereby incorporated byreference, may be used. As will be understood by those of skill in theart, other suitable electronic or mechanical pumps offered by othermanufacturers may be used as well.

Continuing with FIG. 1, an optional clamp 126 is positioned in flow path110 downstream from pump 102. Clamp 126 can compress conduit 108 suchthat fluid flow from pump 102 through flow path 110 is occluded. Suchocclusion is advantageous, e.g., for the transportation and preparationof infusion assembly 100 as described herein. An exemplary clamp 126 isdescribed in U.S. Pat. No. 6,350,253, which is hereby incorporated byreference. However, a variety of other conventional clamps known in theindustry may be used to occlude the flow of fluid from pump 102 throughflow path 110, such as compression clamps, C clamps, roller clamps, andthe like.

An optional filter 128 downstream of clamp 126 separates the fluid fromcontaminates and other undesired particles that may be found within thefluid. Filter 128 also preferably eliminates air from fluid flow path110. One such filter 128 is described in U.S. Pat. No. 6,350,253, whichis hereby incorporated by reference. Of course, other suitable filtersrecognized in the industry may be used to capture undesired particlesand/or remove air from the system.

As further shown in FIG. 1, an optional flow regulator 130 is positionedin continuous flow path 110. Flow regulator 130 sets the continuous andsubstantially constant flow rate of fluid from pump 102 to patient P viatubing 108. In some embodiments, the flow rate may be adjusted to a ratewithin a range, e.g., within a range of about 0.5 to about 14 cubiccentimeters of fluid per hour. Flow regulator 130 may be manuallyadjustable, if desired, and provided with a dial, switch, or lever withan adjustable flow rate control display corresponding to the range offlow rates. For example, the flow rate range may be from about 1 toabout 7 or from about 2 to about 14 cubic centimeters of fluid per hoursuch that the flow rate control display includes a lowermost value of 1and an uppermost value of 7 or a lowermost value of 2 and an uppermostvalue of 14. It will be appreciated that the foregoing flow rate valuesare only exemplary, and in other embodiments, infusion assembly 100 mayhave other flow rates and the flow rate may be adjustable within anotherrange of flow rates. Alternatively, a constant flow regulator (i.e., aregulator that is not adjustable) can be employed. For example, anoptional flow regulating orifice, such as a glass orifice tube 132, maybe employed in the primary or continuous flow path 110. Moreover, inembodiments having a bolus flow path, an optional second flow regulatingorifice 146 may be employed in the bolus flow path.

The particular arrangement of clamp 126, filter 128, and flow regulator130 (or glass tube 132) described herein is merely exemplary. Theseelements, if present, may be arranged in any order, as will be easilyunderstood by those skilled in the art. Desirably, however, glassorifice tube 132 is located downstream of filter 128 when orifice tube132 and filter 128 are provided in infusion assembly 100.

In the exemplary embodiment illustrated in FIG. 1, the conduit 108splits into two flow paths, the continuous or primary flow path 110 andthe bolus flow path 140. A bolus delivery device 200 is in fluidcommunication with the bolus flow path 140. The bolus delivery device200 accumulates a quantity of fluid from the bolus flow path 140 leadingfrom the pump 102 and holds the fluid under pressure until the bolusdose is triggered by a patient operable actuator 202 for release intothe patient P. Generally, the bolus delivery device 200 is configured toreceive fluid, elastically expand to pressurize the fluid, store thepressurized fluid, and dispense the pressurized fluid while avoidingover-administration of a medicinal fluid to the patient. Downstream fromthe bolus delivery device 200, the continuous flow path 110 and thebolus flow path 140 converge into a single flow path. Optionally, aclamp 142, a filter 144, and/or a flow regulating orifice 146 may bepositioned in the bolus flow path 140. The clamp 142 can compress theflow path 140 such that fluid flow from the pump 102 is occluded. Suchocclusion is advantageous, e.g., for the transportation and preparationof the fluid delivery device. Further, although described herein as apatient operable bolus delivery device 200, it will be appreciated thatany user, such as the patient P, a caregiver, a physician, etc., mayoperate the actuator 202 to dispense a bolus dose of the medicinal fluidto the patient P.

Turning now to FIGS. 2-7, the bolus delivery device 200 will bedescribed in greater detail. As shown in FIG. 2, the bolus deliverydevice 200 comprises a housing 204 that supports the actuator 202. Aspreviously described, the actuator 202, configured as a depressiblebutton in the illustrated exemplary embodiment, may be operated by thepatient P to dispense a bolus dose of medicinal fluid from the bolusdelivery device 200. Further, an inlet conduit 206 provides fluid fromthe bolus flow path 140 to the bolus delivery device 200, such that theinlet conduit 206 is in fluid communication with the pump 102, and anoutlet conduit 208 delivers fluid from the bolus delivery device 200 tothe bolus flow path for delivery to the patient.

In addition, the exemplary bolus delivery device 200 includes featuresfor self-priming the device. FIG. 3A provides a side view of the bolusdelivery device 200, with a portion of the housing 204 removed toillustrate the internal configuration of the device 200. As illustratedin FIGS. 2 and 3A, during assembly of the device 200, a removable tab203 is installed that keeps or holds the actuator 202 in a depressed oractivated position. With the actuator 202 depressed by the tab 203 whenthe device 200 is first placed in fluid communication with the pump 102,fluid from the pump flows through the bolus delivery device 200,including through a reservoir 210 disposed within the housing 204 forreceipt of a volume of fluid from the pump 102. As such, the fluiddisplaces the air within the device 200. Once the fluid has flowedthrough the device 200, the tab 203 may be removed, and the actuator 202moves to a extended or non-depressed position as the fluid fills thereservoir 210 of the device 200 (as described in greater detail below)and the fluid pressure within the device increases.

FIG. 3B provides the side view of FIG. 3A with the tab 203 removed. FIG.3C provides the same side view as FIG. 3B but with a compression collarof the device shown as transparent, rather than as opaque as in FIG. 3B.As shown in FIGS. 3A, 3B, and 3C, the activation dome 212 and areservoir seat 214 together define the reservoir 210, i.e., a cavity forreceipt of a bolus volume of fluid from the pump 102. The inlet conduit206 is in fluid communication with the reservoir 210 for providing thefluid to the reservoir. Further, the activation dome 212 and thereservoir seat 214 have suitable dimensions and material properties tolimit their expansion and thereby limit the bolus volume of reservoir210 to a reliable, repeatable, and desirable volume of fluid.

A bladder 216 is disposed in the housing 204 distal to the reservoir210. The bladder 216 is in fluid communication with the reservoir 210for receipt of the fluid from the reservoir, and the bladder 216 is influid communication with the outlet conduit 208 for providing the fluidto the patient P. More particularly, as shown in FIGS. 3A, 3B, and 3C,the actuator 202 is disposed proximal to the reservoir 210 such thatwhen the actuator 202 is actuated, e.g., when the button is depressed bythe patient P, the fluid accumulated in the reservoir 210 flows from thereservoir to the bladder 216. That is, the actuator 202 is in operativecommunication with the reservoir 210 to initiate a flow of the fluidfrom the reservoir 210 to the bladder 216. As the fluid flows into thebladder 216, the bladder expands to accommodate the fluid, and asdescribed in greater detail below, the bladder 216 contracts to dispensethe fluid from the bladder into the outlet conduit 208, through whichthe fluid ultimately flows to the patient P. The bladder 216 may beformed from an elastomer or other suitable material such that thebladder 216 is an expandable bladder. Further, the housing 204 includesinternal ribs 218 that limit the expansion of the bladder 216, as willbe described in more detail herein.

As also illustrated in FIGS. 3A, 3B, and 3C, the reservoir seat 214 islocated between the activation dome 212 and the bladder 216 such thatthe reservoir seat 214 is distal to the activation dome 212 and proximalto the bladder 216. Further, the bladder 216 extends between a proximalconnector 220 and a distal connector 222. As such, the proximalconnector 220 is disposed between the reservoir seat 214 and the bladder216. The inlet conduit 206 and the outlet conduit 208 are each in fluidcommunication with the distal connector 222, which may be configured asa distal manifold 222. The flow regulating orifice 146 (FIG. 1) may bedisposed within the inlet conduit 206, e.g., to help control the refillrate of the bolus delivery device 200. An internal conduit 207 extendsfrom the distal connector 222 to the reservoir 210 to provide the fluidto the reservoir 210. In some embodiments, the flow regulating orificeis made from glass, but in other embodiments, the flow regulatingorifice is made from any suitable flexible material. Other materialsalso may be used to form the flow regulating orifice 146.

The reservoir 210 provides the fluid to the bladder 216 through theproximal connector 220, and the bladder 216 provides the fluid to theoutlet conduit 208 through the distal connector 222. An O-ring 224, orother suitable seal or securement member, secures a proximal end 226 ofthe bladder 216 to the proximal connector 220. Similarly, an O-ring 228,or other suitable seal or securement member, secures a distal end 230 ofthe bladder 216 to the distal connector 222. In the depicted embodiment,the housing 204 also includes a clip 205, or other suitable attachmentmember, e.g., for attaching the bolus delivery device 200 to thepatient's clothing or other support.

Referring to FIGS. 4 and 5, cross-section views of the bolus deliverydevice 200 are provided that help illustrate the operation of the device200. In FIG. 4, the actuator 202 is at its most proximal position, i.e.,the actuator 202 is not actuated or depressed. Further, the reservoir210 is at its maximum volume, which is limited by a compression collar211 (further described below), the activation dome 212 and reservoirseat 214, and the bladder 216 is in a fully relaxed state. In FIG. 5,the actuator is at its most distal position, i.e., the actuator 202 isactuated or depressed to initiate a bolus dose of medicinal fluid to thepatient. Additionally, the reservoir 210 is at its minimum volume, andthe bladder 216 is in a fully expanded state. The actuator 202 isconfigured such that it requires minimal effort to force the fluid outof the reservoir 210 and that, when actuated by the patient P, fluid ispermitted to flow out of the reservoir 210 to the patient withoutfurther action by the patient. More particularly, fluid from the pump102 is stored in the reservoir 210 until the patient P is ready for abolus, and the bolus delivery device 200 prevents flow from thereservoir 210 until a bolus is desired. A piston 232 is axially disposedwithin the reservoir 210 and through an orifice 234 in the reservoirseat 214. The activation dome 212 is connected to the actuator 202 and aproximal end 239 of the piston 232 via an interference fit. Further, aseal member, such as O-ring 236, and a biasing member, such as spring238, are disposed around a distal end 240 of the piston 232, within achannel 215 defined in the reservoir seat 214. The O-ring 236 isdisposed against a distal side 242 of the orifice 234 in the reservoirseat 214, which creates a seal that prevents flow from the reservoir 210into the bladder 216. In other embodiments, other suitable seal members236 may be used to seal the distal side 242 of the orifice 234, i.e., inaddition to or as an alternative to O-ring 236. Moreover, other suitablebiasing members 238 may be used in place of or in addition to spring238. It will be appreciated that the biasing member 238 has a biasingforce, e.g., the spring 238 has a spring force. In some embodiments, acollar 237 is inserted between the seal member 236 and the biasingmember 238. The collar 237 may be a castle washer or the like; a castlewasher has ridge-like features along its top end that resemble a castletower. The biasing member 238 interfaces with a bottom end of the collar237, and the top end of the collar 237 interfaces with a bottom surfaceof the seal member 236, distributing the pressure of the biasing member238 around the seal member 236 to aid in the sealing force provided bythe seal member 236 and biasing member 238. In embodiments in which thecollar 237 is a castle washer, the ridges of the castle washer 237 helpevenly distribute the pressure of the biasing member 238 around the sealmember 236, as well as allow liquid to evacuate the area quickly.

As shown in FIG. 4, when the activation dome 212 is in its fullyexpanded state, the piston 232 pulls the O-ring 236 against thereservoir seat 214. After the reservoir 210 is filled, the patient Ppushes down on the actuator 202 to dispense the bolus. As shown in FIG.5, when the patient P operates or depresses the actuator 202, theactuator 202 compresses the activation dome 212 and displaces the piston232. When displaced or extended into the reservoir seat 214, the piston232 does not pull the O-ring 236. Rather, the spring 238 pushes theO-ring 236 against the reservoir seat 214 and the O-ring 236 is held inplace only by the spring 238. The O-ring 236 is free to slide along thepiston 232, and the spring 238 does not interfere with the movement ofthe piston 232. The fluid pressure from the compressed activation dome212 overcomes the force of the spring 238 and pushes the O-ring 236 awayfrom the reservoir seat orifice 234. Fluid moves past the O-ring 236through the reservoir seat 214 and into the bladder 216 through theproximal connector 220, which connects the bladder 216 to the reservoirseat 214.

The volume of the reservoir 210 is greater than the internal volume ofthe bladder 216 in its relaxed state. The bladder 216 expands toaccommodate the bolus volume, acting as work storage and eliminating theneed for the patient to hold down or continuously actuate the actuator202 to dispense the bolus dose. That is, the bladder 216 stores energyto dispense the bolus automatically. The contraction of the bladder 216forces the fluid through the distal connector 222 into the outletconduit 208 and, ultimately, to the patient P.

The reservoir 210 has a fluid pressure that varies as the volume offluid varies within the reservoir. After the fluid moves from thereservoir 210 to the bladder 216, the fluid pressure inside thereservoir 210 is no longer sufficient to overcome the spring force ofspring 238 or, more generally, the biasing force of the biasing member238. Stated differently, the biasing force overcomes the fluid pressureof the reservoir 210 when the reservoir is substantially empty.Accordingly, the spring 238 extends and pushes the O-ring 236 againstthe distal side 242 of the reservoir seat orifice 234. The seal betweenthe piston 232, reservoir seat 214, and the O-ring 234 prevents flowfrom the expanded bladder 216 back into the activation dome 212. Fluidfrom the pump 102 refills the reservoir 210, expanding the activationdome 212 and gradually returning the piston 232 to its originalposition. However, the patient P can actuate or depress the actuator 202at any time and receive a partial bolus dose. There is no lockoutmechanism to prevent a partial bolus while the reservoir 210 is in arefill state. Nonetheless, as described below, the bolus delivery device200 incorporates features for preventing over-administration ofmedication, e.g., through a larger bolus dose than the maximum expandedvolume of the bladder 216.

The piston 232 prevents leakage past the sealing O-ring 236 and therebyprevents leakage within or internal to the bolus delivery device 200. Asthe reservoir 210 fills, the internal pressure increases to match thatof the elastomeric pump 102, i.e., the fluid source. Increased pressurein the reservoir 210 expands the activation dome 212, which pulls thepiston 232 against the sealing O-ring 236, increasing the sealing forceagainst the reservoir seat 214. The configuration of the activation dome212, the piston 232, and the O-ring 236 ensures the device 200 operatesin a wider pressure range, e.g., up to about 30 psi, to accommodatedifferent sizes of the pump 102.

Turning now to FIGS. 6 and 7, the internal configuration of the bolusdelivery device 200 in the vicinity of the bladder 216 will be describedin greater detail. FIG. 6 provides a cross-section view of the distalportion of the device 200 with the bladder 216 in its fully relaxed orcontracted state. FIG. 7 provides a cross-section view of the distalportion of the device 200 with the bladder 216 in its fully expandedstate. As illustrated in FIG. 7, the proximal connector 220 includes anoutlet 244 that extends into the bladder 216. The O-ring 224 secures theproximal end 226 of the bladder 216 to the outlet 244. Moreover, thedistal connector 222 includes an inlet 246 that extends into the bladder216. The O-ring 228 secures the distal end 230 of the bladder 216 to theinlet 246. Fluid from the reservoir 210 is provided through the outlet244, and the fluid egresses from or exits the bladder 216 to flow to thepatient through the inlet 246. As also illustrated in FIGS. 6 and 7, theinternal conduit 207 extends directly to the reservoir 210, i.e., to theactivation dome 212 or the reservoir seat 214, to provide fluid from thepump 102 to the reservoir 210.

Further, as shown in the depicted embodiment, the housing 204 definesribs 218 along an internal surface 250 of the housing 204. Asillustrated most clearly in FIG. 7, the ribs 218 constrain the expandedstate of the bladder 216 to a desirable volume. Thus, in the event thatthe bladder 216 cannot empty and return to its contracted state, e.g.,an occlusion in the outlet conduit 208 or a distal component preventsthe bladder 216 from dispensing the fluid, the reservoir 210 willcontinue to refill but the patient P will be unable to actuate ordepress the actuator 202. More specifically, the bladder 216 will notaccommodate any additional fluid in its fully expanded state and,therefore, the activation dome 212 cannot be compressed. Accordingly, alarger bolus dose cannot be administered, i.e., the ribs 218 of housing204 constrain the expansion of bladder 216 to preventover-administration of medication.

Moreover, the housing 204 includes features at a proximal portion of thedevice 200 that work with the activation dome 212 to control bolusvolume. For instance, features within the housing 204 constrain themovement of the actuator 202 and the activation dome 212. Moreparticularly, when the reservoir 210 is full, the activation dome 212reaches a final expanded volume that is limited by a compression collar211 that extends about the activation dome 212. For instance, theactivation dome 212 may be made from a material such as silicone thatcould over-inflate if not limited by a feature such as the compressioncollar 211. Further, in some embodiments, the physical dimensions of theactuator 202 and housing 204, as well as the seal created by the piston232, spring 238, and O-ring 236 assembly, also may limit the expansionof the activation dome 212. These constraints help preventover-expansion of the activation dome 212, such that the activation dome212 cannot expand beyond a pre-determined maximum volume.

Additionally, referring back to FIGS. 4 and 5, a stop 252 limits thedistal movement of the actuator 202, and the reservoir seat 214 limitsthe distal movement of the activation dome 212. More specifically, theactuator 202 includes a guide extension 254 that moves distally andproximally within a guide slot 256 defined by the housing 204. Themovement of the guide extension 254 within the guide slot 256 helpsensure the stop 252 catches or seats within a groove 258 defined in theactuator 202 to stop, and thereby constrain, the distal movement of theactuator 202 in a fully actuated or fully depressed state, shown in FIG.5. Moreover, when the actuator 202 is fully actuated or depressed, theactivation dome 212 is collapsed against the reservoir seat 214. Theactuator 202 includes a distal end 260 that presses the activation dome212 against an internal surface 262 of the reservoir seat 214. Asillustrated in FIG. 5, the distal end 260 of the actuator 202 generallyis shaped complementarily to the internal surface 262 of the reservoirseat 214 such that the activation dome 212 generally conforms to theshape of the reservoir seat internal surface 262 when the activationdome 212 is substantially collapsed and reservoir 210 is substantiallyempty.

The housing 204 may also include one or more features for minimizingstresses on various components within the bolus delivery device 200. Forexample, referring back to FIGS. 3B and 3C, a strain relief 264 may beused at the distal connector 222 to minimize the stress to the inletconduit 206, internal conduit 207, and/or outlet conduit 208, which areall connected to the distal connector 222. As shown in FIGS. 3B and 3C,the strain relief 264 includes two or more ridges 266 that help relievethe stress on the conduits 206, 207, 208. The housing 204 also mayincorporate other features for reducing and/or eliminating stress onother components of the bolus delivery device 200.

Accordingly, it will be appreciated that the release rate of the bolusdose of the fluid to the patient P is controlled by at least in part bythe decompression of the bladder 216. Other features of the infusionassembly 100 downstream of the bolus delivery device 200, such as thediameter of the catheter 114, may also control the release rate of thefluid to the patient P. Advantageously, the patient P does not have toprovide pressure to force fluid out of the bolus delivery device 200into the bolus flow path 140. Rather, the patient P can simply actuateor depress the actuator 202 to administer the bolus dose. If the patientP activates or operates the actuator 202 prior to the time the bolusreservoir 210 has filled to its capacity, the patient P receives lessthan the full amount of the bolus dose. In effect, this prevents thepatient P from self-administering more than the maximum desired amountof fluid per the time specified as a bolus dose.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they include structural elementsthat do not differ from the literal language of the claims or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal language of the claims.

What is claimed is:
 1. A bolus delivery device, comprising: a housing; areservoir disposed within the housing for receipt of a volume of afluid, the reservoir defined by an activation dome and a reservoir seat;a piston axially disposed within the reservoir and extending through anorifice in the reservoir seat; a seal member disposed around a distalend of the piston and against a distal end of the orifice of thereservoir seat, where the seal member is free to slide along the piston;a bladder disposed in the housing, the bladder in fluid communicationwith the reservoir for receipt of the fluid from the reservoir; anactuator; an inlet conduit in fluid communication with the reservoir forproviding the fluid to the reservoir, and an outlet conduit in fluidcommunication with the bladder for providing the fluid to a patient,wherein the actuator is in operative communication with the reservoir toinitiate a flow of the fluid from the reservoir to the bladder, andwherein the bladder expands as the bladder receives the fluid andcontracts as the bladder dispenses the fluid.
 2. The bolus deliverydevice of claim 1, wherein the reservoir seat is located between theactivation dome and the bladder such that the reservoir seat is distalto the activation dome and proximal to the bladder.
 3. The bolusdelivery device of claim 1, further comprising: a biasing memberdisposed around the distal end of the piston, wherein the activationdome is connected to the actuator and the proximal end of the pistonsuch that operating the actuator displaces the piston to displace theseal member and initiate the flow of fluid from the reservoir to thebladder.
 4. The bolus delivery device of claim 1, wherein the housingdefines ribs that limit the expansion of the bladder.
 5. The bolusdelivery device of claim 1, wherein the bladder extends between aproximal connector and a distal connector, and wherein the inlet conduitis in fluid communication with the distal connector and the outletconduit is in fluid communication with the distal connector.
 6. Thebolus delivery device of claim 1, further comprising: a stop thatcatches in a groove defined in the actuator to limit the distal movementof the actuator.
 7. The bolus delivery device of claim 1, wherein theactuator is operable by the patient to initiate a release of fluid fromthe bolus delivery device to the patient, and wherein the actuator isconfigured such that it requires minimal effort to force the fluid outof the bolus delivery device and that, when actuated by the patient,fluid is permitted to flow out of the bolus delivery device to thepatient without further action by the patient.
 8. The bolus deliverydevice of claim 1, further comprising: a removable tab that holds theactuator in a depressed position to self-prime the bolus deliverydevice.
 9. The bolus delivery device of claim 3, wherein the reservoirhas a fluid pressure that varies as the volume of the fluid varieswithin the reservoir, and wherein the biasing member has a biasing forcethat overcomes the fluid pressure of the reservoir when the reservoir issubstantially empty to push the seal member against the distal side ofthe reservoir seat.
 10. The bolus delivery device of claim 3, furthercomprising: a collar disposed between the seal member and the biasingmember.
 11. The bolus delivery device of claim 5, further comprising: aninternal conduit extending from the distal connector to the reservoir,the internal conduit providing fluid communication between the inletconduit and the reservoir.
 12. An infusion assembly, comprising: anelastomeric pump configured to provide a fluid under pressure; acontinuous flow path in fluid communication with the pump for providinga continuous and substantially constant flow rate of fluid from thepump; a bolus flow path for the delivery of a bolus dose of the fluid;and a bolus delivery device in fluid communication with the bolus flowpath and configured to receive fluid from the pump, the bolus deliverydevice including: a housing, a reservoir disposed within the housing forreceipt of a volume of a fluid, the reservoir defined by an activationdome and a reservoir seat, a piston axially disposed within thereservoir and extending through an orifice in the reservoir seat, a sealmember disposed around a distal end of the piston and against a distalend of the orifice of the reservoir seat, where the seal member is freeto slide along the piston; a bladder disposed in the housing, thebladder in fluid communication with the reservoir for receipt of thefluid from the reservoir, an actuator operable by a patient, an inletconduit in fluid communication with the reservoir for providing thefluid to the reservoir, and an outlet conduit in fluid communicationwith the bladder for providing the fluid to the patient, wherein theactuator is in operative communication with the reservoir to initiate aflow of the fluid from the reservoir to the bladder, and wherein thebladder expands as the bladder receives the fluid and contracts as thebladder dispenses the fluid.
 13. The infusion assembly of claim 12,wherein the pump provides the fluid under a pressure of up to about 30psi.
 14. The infusion assembly of claim 12, wherein the pump providesthe fluid under a pressure within a range of about 10 psi to about 30psi.
 15. The infusion assembly of claim 12, wherein the pump providesthe fluid under a pressure within a range of about 14 psi to about 25psi.
 16. A bolus delivery device, comprising: a housing; a reservoirdisposed within the housing for receipt of a volume of a fluid, thereservoir defined by an activation dome and a reservoir seat; a bladderdisposed in the housing, the bladder in fluid communication with thereservoir for receipt of the fluid from the reservoir; and a pistonaxially disposed within the reservoir, the piston having a proximal endand a distal end; and a seal member disposed around the distal end ofthe piston and against a distal side of an orifice in the reservoirseat, where the seal member is free to slide along the piston, whereinthe activation dome is connected to the proximal end of the piston suchthat displacement of the piston initiates a flow of the fluid from thereservoir to the bladder.
 17. The infusion assembly of claim 16, whereinthe housing defines ribs that limit the expansion of the bladder. 18.The infusion assembly of claim 16, further comprising: an inlet conduitin fluid communication with the reservoir for providing the fluid to thereservoir; an outlet conduit in fluid communication with the bladder forproviding the fluid to a patient; a proximal connector; a distalconnector; and an internal conduit extending from the distal connectorto the reservoir, wherein the bladder extends from the proximalconnector to the distal connector, wherein the inlet conduit is in fluidcommunication with the distal connector and the outlet conduit is influid communication with the distal connector, and wherein the internalconduit provides fluid communication between the inlet conduit and thereservoir.
 19. A bolus delivery device, comprising: a housing; areservoir disposed within the housing for receipt of a volume of afluid, the reservoir defined by an activation dome and a reservoir seat;a piston axially disposed within the reservoir and extending through anorifice in the reservoir seat, a seal member disposed around a distalend of the piston and against a distal end of the orifice of thereservoir seat; a biasing member disposed around the distal end of thepiston; a bladder disposed in the housing, the bladder in fluidcommunication with the reservoir for receipt of the fluid from thereservoir; an actuator; an inlet conduit in fluid communication with thereservoir for providing the fluid to the reservoir, and an outletconduit in fluid communication with the bladder for providing the fluidto a patient, wherein the actuator is in operative communication withthe reservoir to initiate a flow of the fluid from the reservoir to thebladder, and wherein the bladder expands as the bladder receives thefluid and contracts as the bladder dispenses the fluid, and wherein thereservoir has a fluid pressure that varies as the volume of the fluidvaries within the reservoir, and wherein the biasing member has abiasing force that overcomes the fluid pressure of the reservoir whenthe reservoir is substantially empty to push the seal member against thedistal side of the reservoir seat.